Tuesday, October 10, 2017

Mousetrap Car Demonstration at Nursing Home

Last week I gave a demonstration of mousetrap cars for two different groups in a nursing home. I was concerned how interesting they would find my presentation but it was well received and they are looking forward to me presenting another project idea, I proposed model aviation.

Mousetrap Car Race 

Below is an outline of what I wanted to present, it worked well for a 40 minute presentation:

My Basic Outline for Mousetrap Car Demonstration

* Talk about my father and his farm machinery inventions.

* My interest in model airplanes led to building and flying events for kids, I wanted to expand to more types of model projects and came across mousetrap cars.

* I watched some videos of mousetrap cars on the Internet and was amazed at the number of views.

First Mousetrap Car I Design Built from Bamboo

* My purchase of the Doc Fizzix book on mousetrap cars gave me the background to design my own cars using different materials; the first car was built mainly from bamboo. I also purchased Doc Fizzix kits and started an online friendship with Doc Fizzix, Alden Balmer a truly outstanding teacher.

College for Kids Class Mousetrap Cars

* In teaching a project building class at local university, I had students build mousetrap cars every year.

Lever Arm Attached to Spring on Mousetrap Car

* Mousetrap cars are a wonderful for teaching force and motion, I would mention Newton’s Laws of Motion especially the first law relating to getting an object at rest moving.  

Large Drive Wheel Mousetrap Car

* I would demonstrate mousetrap cars with long lever arms which moved slowly, cars with short leverage arms were much faster, and a mousetrap car with a very large drive wheel is also slower.

Start of Mousetrap Car Race

* There would be a mousetrap car race between two cars. By attaching a length of yarn to mousetrap car, a person sitting could easily release the car.

Bill Kuhl

Related Links





Monday, October 9, 2017

Oktoberflug Free Flight Contest

It was the best weather this year for the final outdoor free flight contest in Minnesota. The wind was very light in the morning but switched around almost 360 degrees throughout the day. To start out the morning drift was towards the trees which worried me, better flyers were getting their models to fly over the trees. I flew my e36 Super Pearl before any contest flights with fairly short DT to avoid the trees; it flew perfect as it had the last time.

Gordon Dona Flew Model Past the Trees

My main goal was to get some longer flights on my Wilbur rubber model, at the last contest when I increased turns from 200 to 400 it was going straight up and sliding backwards. Adding some side and down thrust appears to have cured that. It stalled in the glide somewhat but it caught some lift on one flight and was staying up even with the stalls, next flight I had fixed the glide but didn’t find any lift. I still did not have anywhere near maximum turns but it was drifting towards the corn almost 180 degrees from the drift before. It is fun to see the propeller fold back and I did get in three contest flights with no damage.

Wilbur Rubber Model Folded Prop
Wilbur Landed

Before the wind came up I wanted to try my Peewee 30 model Basic Yeller. The first flight did not get super high but the glide was perfect and stayed up until the DT brought it down but now the drift was behind us. I tried another flight and it went to the right into the ground, no damage. Thinking it was just a bad launch I tried it again and this time there was damage, broke the pylon off. I noticed there were only two wood screws on one side holding the motor on. My thought is that it was loose before causing sidethrust giving a severe turn. I plan to fix it with bolts instead of wood screws.

Basic Yeller Landed Behind Pit Area

Pylon Broken in Crash

I flew my Polecat X P30 in the contest for the first time and it went very well. Still I was not up to maximum turns which no doubt would have taken it higher. I am using the 3/32” rubber motor that gives a long run but a slow climb. During the long run there is a good chance it will encounter lift which it did but the pop off wing brought it quickly down.

My Polecat X Brought Down by DT Before Cornfield

Just before I left I tried one flight of my Jetstream towline from a launcher. By now the wind was up and I was not familiar with that. It rose quickly and I stopped running but the wind took it up like a kite until it came off the hook and banked sharp into the ground. Only damaged one wing tip but I can see I have more to learn about towing in different wind conditions.

Starduster X

I used my binoculars when timing flights for others as I want to get better at following the model this way.  Also hoping to take some video but I only got video of a Starduster X flying one flight. At least I had rubber boots for this contest and did not have to leave with wet feet from the morning dew. 

Pearl e36 with my new Boots 
Flying Aces Moth

Bill Kuhl

Related Articles




P. Visser's "Wilbur" Nostalgia Mulvihill per Zaic '53    Item ID  NOSR9

http://volareproducts.com/   Propeller Blanks

http://www.pearlfreeflight.com/Buy.html  Pearl Free Flight website to Purchase Polecat X

Starduster Video

Tuesday, October 3, 2017

Why I Like Free Flight Part II

I have been overwhelmed by the number of views to my last post so I have decided to expand on that and share a little more about myself.  One thing that bothers me, is wasting anything and I am really impressed by things that are efficient.  I know I could do a better job of not wasting and I realize that other people have different needs; you are not going to pull a horse trailer with a Prius. What impresses me most of about my hybrid car is that the engineering that has been done in so many aspects to improve the gas mileage. The factors that contribute to the total result working together are many but the end result is I drive car that averages 60 mpg in the warmer months. Just some of the areas where improvements were made were recapturing energy from coasting and braking, drag reduction, increased thermal efficiency in the internal combustion engine, constantly variable transmission, and using battery power to help power the car some of the time.  It is a total system working together.

Typical Large Glow Engine Powered Free Flight - Dave Edmondson
Hybrid Car System of Engineering Ideas Work Together

Now how does this relate to free flight?  I see the competition free flight airplane as a total system that is optimized in many ways to give the longest duration given the constraints such as size, power, and minimum weight.  There are so many factors that can be optimized such as; the aspects of the construction materials such as balsa density and grain, building structure types, covering material, and warps built in to give the proper flight path for a free flying model airplane. With power system if it is a motor it should have a high power to weight ratio given constraints to the competition classification. Aspects of the propeller such as diameter, pitch, and pitch ratio can make a difference in power models including rubber powered models.

This Balsa Structure Made for Very Stiff Balsa Wing

Bob Hanford has Flown Free Flight Contests from a Young Age 
Beyond keeping your competition free flight model aloft consistently above a specified length of time, you want it to come down reliably after that specified time. This is where the dethermalizer system (DT) comes in to bring the model down quickly without damage while lifting air (thermals) can be trying to carry it higher still. There are many systems that are used but it is often a tradeoff between weight, cost, and what the builder prefers to use. The DT system can often take a fair amount of tweaking to work as reliable as possible.

Pressurized Fuel System and DT Timer on Dan Berry's Plane
Now after the model is built, you need to test fly it. With no control from the ground to save it should it fly in a path that results in a crash, you develop procedures to slowly lengthen the time of the motor run and length of glide before DT. If this model is rubber powered you use less turns of the rubber motor but you must be aware that the model might fly radically different with more turns of the rubber and increased power. For any type of model test glides are done first but this might only give a very rough idea how it will fly under power.  To me this is the most interesting and sometimes frustrating aspect of free flight models, the adjustment process. In getting your model to fly properly it calls on your knowledge of aerodynamic theory and putting it to practical use. Like any good experiment you want to change only a single variable at a time.

Rubber Powered Model Needs Propeller and Rubber Strands Matched - Skeeter Surgine

If you are flying indoor free flight it is a rather controlled environment but flying outdoor free flight which I have greater interest in now, has many additional aspects you must consider. There is the thermal air currents that you want to launch into but there is also sinking air, turbulence, and wind that will drift your model to parts unknown.  This year I purchased a used radio telemetry system which am I learning to use. A small radio transmitter is attached to the airplane that sends out a signal that you locate with a directional antenna.

Tiny RF Location Transmitter

Directional Antenna and Receiver 

My Indoor Rubber Powered Model
As the investment guru Jim Cramer likes to point out, here is the bottom line. Outdoor free flight model aviation gives one endless opportunities to learn engineering skills and practice real world experiments. By just timing the flight duration over a series of many flights you can see the results of many factors working together in a system operating in a changing environment. As a bonus for those of us passionate with the hobby, the thrill of seeing the model airplane flying with no external control is a major high.

Note: I did not mention gliders, topic for another post.

Hank Sperzel a Big Inspiration to Me

Bill Kuhl

Related Blog Articles 

Related Links to My Short Videos
https://youtu.be/8efeH5pGhe8 - My Background in Free Flight Model Airplanes
https://youtu.be/pQnNaRu4ah8 - Learning to use Walston Tracking System
https://youtu.be/2hifn3N3OZY - Guillow's Lancer with fuse DT
https://youtu.be/abp5nQBiHnU - Texas Timers Micro DT
https://youtu.be/LFCQFKum2QU - High Speed of Glow Powered Free Flight Ruth Bane

Thursday, September 28, 2017

Why I Like Free Flight Model Aviation

Why do I like free flight?  I fly other types of model airplanes also, mainly RC sailplanes and electric park flyers. Where I live there really is not enough open space for larger free flight models but there is enough to fly radio control and control line. The last couple of years I have been spending much more of my model aviation time flying competition free flight models while in previous years I flew very basic free flight models.  My contest success has not been good but I have a great time at contests and I am always learning which is what I like most about the hobby. Better success at contests will come eventually. I realize that many of the people at contests have been flying free flight competitively since they were a teenager. My model airplane experience goes back that far but not free flight. Everyone has been more than willing to help me with free flight.

I like to build model airplanes, especially free flight as I think the quality of your building more directly is apparent in the flight characteristics of completed model. Small things matter such as using the correct wood density and grain type in the wood. The slightest warp can make be a major difference in flight characteristics. The adjustment process for a new plane can be interesting and frustrating but when you a build a model that takes little adjustment from the start that is a major thrill also.

Jetstream Towline Glider has been Major Challenge this Year
Starduster e36 was Challenging for me this Year
Peck Sky Bunny Typical Free Flight I Would Fly 

I find it challenging. There are so many different types of models with unique challenges; part of it is how the model is powered. This year I worked with rubber power, electric, gliders towed up on hi-start and by human running, Co2 engine, and a small glow engine. For dethermalizers I worked with several types including fuse, electronic servo, electronic band burner, mechanical, and viscous. Deployment of the DT I used popup stab, popoff wing, and popup front of wing.

Polecat X p30 PopOff Wing

My Super Pearl E36 after Flight at 2017 Nats
PeeWee 30 Model Built from Plans was a Fun Challenge
Completed Model at 2017 Nats
Electronic Timer on BMJR Sky Demon E20 
Improved DT Setup for BMJR e36 Starduster

A Few Things I Learned this Year in Free Flight

 *  I learned this year that CG (center of gravity) on the plans is where it needs to be at least for a beginner and if the model does not fly correctly at that location, change the incidence do not keep moving the CG.

*  I am learning how critical getting the correct trim settings in high speed phases of flight are and how necessary it is to slowly increase the motor run time. New issues can be seen further into the run that were not seen in the beginning of the flight. 

*  I am learning that flying surfaces cannot be moving around, rubber bands must hold tight, wing and stab need to be keyed so there is no shifting in flight. The structure needs to be stiff as well and weaknesses will often not show by visual inspection of the plane. When your plane hits the ground often it does damage that you do not see but twisting the model gently it might show up.

Bill Kuhl

PS.  Thank you for reading my blog posts, I am just amazed that views recently went over the quarter million mark.

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Tuesday, September 19, 2017

Exploring With Rod and Reel

I have been spending more time fishing recently as earlier this summer I was trying to get my free flight model airplanes adjusted for the Nats Free Flight contest the last week of July in Muncie Indiana. My motives for fishing recently have been more to try to understand the current fishing environment and how I could improve my chances of catching fish. Besides the fishing around the Winona area I have also fished some in Rochester while visiting my mother. 

No Luck Fishing Zumbro River by Apache Mall

Small Dam on Zumbro

Just out of curiosity I have tried fishing with worms in a couple of the warm water streams in Rochester, Bear Creek and the Zumbro River behind Apache Mall Shopping Center.  As a kid growing up in Rochester I remember catching small rough fish such as chubs, shiners, and suckers about as fast as I could bait the hook. After several attempts of fishing those streams in Rochester I have not caught a fish. I did have a small fish on in the Zumbro below Mayowood dam. It really makes me wonder what is different, is it the water quality or predators?  Completely out of curiosity I fished the small pond that is for drainage by Apache Mall and caught tiny bluegills right away.  I have heard about how bullheads have disappeared which is a fish that can live in almost any water. This article maintains there decreased numbers are related to cleaner water - “  Bullheads Drop Off - Cleaner water has led to the decline of the celebrated fish in southern Minnesota”, could other rough fish have disappeared because the water is too clean?

Sunfish Quarry Hill Nature Center Pond

New Dock at Quarry Hill

Turtle Came After the Worm

Recently I tried fishing in the man made pond at the Quarry Hill Nature Center using worms for bait. The pond is somewhat weedy but the tiny sunfish take the worms about as fast as you can bait your hook. I also had a turtle come after the worm but made sure the turtle was not hooked. My understanding is there is also largemouth bass and northern pike in the pond.

Crappie From Cascade Lake
One of Cascade Lakes

The other area I have fished is the Cascade Lakes. These gravel pits are fairly large and have some artificial habit created. So far I have caught small largemouth bass, sunfish and a crappie. I did witness someone catch a good size bass, another time someone caught a large carp.

Northern Pike caught in Mississippi River

Walleye caught from shore of Mississippi

I have also tried fishing from the banks of the Mississippi River in Winona where I live using artificial lures.  Sometimes I had good luck but more often I caught nothing. The one spot while casting off a dock I caught a small northern pike and a walleye within about 20 minutes, two other times I caught nothing.  

Like most things in life fishing changes, sometimes for the better and other times for the worse. It is fun exploring with rod and reel trying to discover the patterns of what is under the surface of the water.

Bill Kuhl

Related Links


Eric Atherton: Bass might be top attraction at Cascade Lake


Friday, September 8, 2017

Cause & Effect - Educating Myself on Fishing

Cause and effect is the principle of causality, establishing one event or action as the direct result of another.” Wikipedia 

Lately I have been thinking a lot about “cause and effect” in regards to my hobbies.

Small Trout Stream

This past fishing season I have decided to take my fishing a little more serious and see it as an opportunity to learn. The majority of the fishing I have done has been fishing for trout in the small streams within 20 miles of where I live. I have also fished from a small lake, Lake Winona just several blocks from where I live. In trout fishing I have been pretty successful using the same Rapala lure for several years and fished it also in Lake Winona and did fairly well but never great, for sure it does not work well when the weeds are thick.

Lake Winona

What I had learned to catch trout in a small stream is you had to keep walking and only fish a short time in each likely spot, doing this I did pretty well. Looking back maybe 15 years ago it seemed like every small stream had trout you could catch, even within the city boundaries. In later years when I tried fishing those streams I have had no luck at all. The past couple of years even where I had good luck before I was not catching anything but yet I heard of other people catching many trout. I starting trying new spots and found I was catching fish again. Streams are constantly changing, especially after heavy rains or floods. Improvements have been made by different organizations to some streams and it is helping. 

Brown Trout from Small Stream

This spring I had exceptionally good luck fishing for largemouth bass in Lake Winona just after the season had opened. I realize now it was because the fish were still spawning and the large fish were really active for a few days. There were a couple of evenings I was catching huge fish on almost every cast but within a week it was tough to catch a single small fish. Then I would fish for a couple of hours in the evening and catch absolutely nothing. Since then I have done some reading and learned much from Doug at Hogline Bait & Tackle.  I try to buy locally from small merchants and find the advice they give me is well worth any additional cost from large retailers or online.

Largemouth Bass Caught Early Season

 Recently I came across an article online from a Sport Illustrated article about largemouth bass from an expert on the ecology of the fish, Dr. George W. Bennett. A few items peaked my interest and really pointed out my blaming the body of water for poor fishing really was incorrect. Like so many things that might seem like mainly luck, those people that excel at mastering the nuances do way better than the majority of the people with way less experience and knowledge.

Great article on Largemouth Bass

It is also interesting how the fish can be interested in a new lure but after seeing so many other fish caught with the lure they will be way less likely to be caught on that lure. I thought it was just seeing other fish get caught in an area that scared others away, I have seen that happen and made a video about it.

https://www.facebook.com/Hogline-Bait-Tackle-310712119329619/  Hogline Bait and Tackle